This invention relates to energy storage.
It has already been proposed to store energy by causing a large diameter fly-wheel to spin about a central axis and applying the energy to be stored to the spinning of the wheel. Energy is withdrawn from the spinning wheel as and when it is required.
It can be shown that the specific energy per unit of mass of a flywheel system may be increased by increasing the radius of the orbit of the outer part of the wheel. However, in a conventional system any mass on that orbit has to be connected to the hub by restraining means such as spokes or webs, which are in themselves massive. The latter mass may offset any gain in specific energy obtained by increasing the radius.